title: Beyond the GIST: mesenchymal tumors of the stomach.
abstract: Intramural gastric masses arise in the wall of the stomach (generally within the submucosa or muscularis propria), often with intact overlying mucosa. These tumors are typically mesenchymal in origin and have overlapping radiologic appearances. A combination of features such as location, attenuation, enhancement, and growth pattern may suggest one diagnosis over another. Gastrointestinal stromal tumors (GISTs) account for the majority of intramural tumors and can vary widely in appearance, from small intraluminal lesions to exophytic masses that protrude into the peritoneal cavity, commonly with areas of hemorrhage or necrosis. A well-circumscribed mass measuring -70 to -120 HU is a lipoma. Leiomyomas usually manifest as low-attenuation masses at the gastric cardia. Homogeneous attenuation is a noteworthy characteristic of schwannomas, particularly for larger lesions that might otherwise be mistaken for GISTs. A hypervascular mass in the antrum is a common manifestation of glomus tumors. Hemangiomas are also hypervascular but often manifest in childhood. Inflammatory fibroid polyps usually arise as a polypoid mass in the antrum. Inflammatory myofibroblastic tumors are infiltrative neoplasms with a propensity for local recurrence. Plexiform fibromyxomas are rare, usually antral tumors. Carcinoid tumors are epithelial in origin, but often submucosal in location, and therefore should be distinguished from other intramural lesions. Multiple carcinoid tumors are associated with hypergastrinemia, either in the setting of chronic atrophic gastritis or Zollinger-Ellison syndrome. Sporadic solitary carcinoid tumors not associated with hypergastrinemia have a higher rate of metastasis. Histopathologic analysis, including immunohistochemistry, is usually required for diagnosis of intramural masses.
authors.affiliation: Departments of Diagnostic Radiology and Pathology, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Unit 1473, Houston, TX 77030; Department of Radiology, Mayo Clinic, Tucson, Ariz.
authors.forename: Hyunseon C
authors.initials: HC
authors.lastname: Kang
authors.forename: Christine O
authors.initials: CO
authors.lastname: Menias
authors.forename: Ayman H
authors.initials: AH
authors.lastname: Gaballah
authors.forename: Stuti
authors.initials: S
authors.lastname: Shroff
authors.forename: Melissa W
authors.initials: MW
authors.lastname: Taggart
authors.forename: Naveen
authors.initials: N
authors.lastname: Garg
authors.forename: Khaled M
authors.initials: KM
authors.lastname: Elsayes
mesh_terms: D003287:Contrast Media; D003937:Diagnosis, Differential; D003952:Diagnostic Imaging; D018450:Disease Progression; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D008648:Mesoderm / Q000473:pathology; D013270:Stomach / Q000033:anatomy & histology; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000473:pathology
chemical_list: D003287:Contrast Media